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Review: Men and Women Assigned to Projects
Explanation
Since the rightmost column is a sum of the other two columns,
the table gives us a series of equations:
Although most people prefer solving by substitution,
combination will be faster here. We can subtract the last equation from the
first equation to get
Adding this last equation to the second equation of the
original set, we get
Therefore, 
.
The correct answer is (D).
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